We are looking to do more free-camping in future trips. We've got a 100w Lithium battery and a Kings 200w solar blanket. We would like to be able to see what power is coming into our system and what power is being consumed at any given time. Keen to hear solutions used by others. Last time out we free-camped for up to 3 days at a a time. Never ran out of power, but had little to no knowledge of what was going in or how fast we were consuming what we had.
I have 4 x 26AH batteries, 120 watts solar & Victron MPPT 100/20 Bluetooth controller (a bit overkill but allows future expansion if I ever feel the need) & it's located near the batteries where it should be, not on the solar panel which is the wrong place.
The controller gives you all the input output data on your phone. But after a few weeks I didn't bother looking at it & one has a surprising good gut feel for what is happening. But it is handy for technical reference.
Also got some simply meters from Jaycar which from day to day casual glance, they are great & surprisingly accurate.
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50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.
It sounds like you have very little power usage. Unfortunately you cannot use battery voltage to estimate how much battery capacity you have remaining.
Costly I know but accurate if wired correctly and good information for you. if you do add to your system at a later stage then gat a Victron solar controller too.
You can attach one of these as well to give you an indication of what your solar panels are generating.
I have tested a few battery monitors over the last 15 or so years. Votronic, BM-1, Victron, BEP, Juntek, Junctek and a few other cheapies.
Currently I have both a Victron 500A SmartShunt and a Junctek KH140F.
I have absolutely no hesitation in recommending the Junctek over them all despite being a Victron fan. Available via Ebay, AliExpress etc. Mine purchased from this store: https://www.aliexpress.com/item/1005005293126063.html
Out of interest i did a little searching and you might like this comment.
For seeing watts in and out, and relative remaining capacity, it's just an outstanding value. I don't use any of the switching capability, and not sure if I would want to rely on it for highly sensitive high value systems, but for the RV it's just dandy.
BTW, it's pronounced 'joontek', not junk-tech. But I get it.
For anyone considering a less expensive shunt you may wish to read this link or go to the site and do a search.